User Fields is a robust feature in Paid Memberships Pro to create custom profile fields for your membership site. This post covers a lesser known feature of that Add On: the field’s custom save_function. You can use a custom callback function for any field to modify how and where the field’s value is saved.

Banner Image for How to Use a Custom Callback Function For Use Profile Fields

Table of contents

Saving User Fields With a Custom Callback Function

Every user field can be extended with a custom save_function. This callback function opens up a whole range of possibilities that you or your developer may incorporate to extend how a field data is processed, such as:

  • Format field input data before saving to the database.
  • Perform server-side data verification such as validate a member’s location, age, qualifications, and more.
  • Save the field input to any database table in your WordPress site, not just the default location in usermeta.

Using the save_function Custom Callback

Custom callback functions for a field require that you do two things:

  1. Write the custom function.
  2. Add the custom function to the field array in your custom user fields code. The save_function field attribute accepts a string value of the callback function’s name.
'save_function' => 'my_custom_callback_function'

The save function is attached to a specific user field you create either with the User Fields Settings page or via custom code. Here are two examples of adding a save_function to a user field.

Recipe #1: Create User Field and Save Function in Custom Code

Here is a basic example of setting a callback function with the save_function option on line 17.

<?php
// Create a registration form field with a custom callback
function my_pmpro_user_field_example_save_function() {
// Don't break if PMPro is out of date or not loaded.
if ( ! function_exists( 'pmpro_add_user_field' ) ) {
return false;
}
// define the fields
$fields = array();
// Basic Text Field Example
$fields[] = new PMPro_Field(
'my_field_name', // input field name, used as meta key
'text', // field type
array(
'label' => 'My Field Label', // field label
'profile' => true, // display on user profile
'save_function' => 'my_custom_callback_function', // use a custom callback function
)
);
foreach ( $fields as $field ) {
pmpro_add_user_field(
'checkout_boxes', // location on checkout page
$field // PMPro_Field object
);
}
}
add_action( 'init', 'my_pmpro_user_field_example_save_function' );
// Custom callback function
function my_custom_callback_function( $field_value ) {
// Do something
}
view raw save-function-custom-callback.php hosted with ❤ by GitHub

Recipe #2: Filter a User Field Created in Settings to Add a Save Function

For this example, the user field would have already been created on the Memberships > Settings > User Fields screen in the WordPress admin.

This code extends that field to add your custom save_function. Update the field_name on line 19 for your user field name.

Copy
<?php
/**
 * Example of adding a save function custom callback function to a field
 * using the "pmpro_add_user_field" filter hook.
 *
 * title: Example add custom callback save function for a user field.
 * layout: snippet-example
 * collection: user-fields
 * category: custom-fields
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_pmpro_user_field_add_save_function_example( $field, $where ) {
 // Match our field name
 if ( 'field_name' === $field->name ) {
 // Add save function for our field.
 $field->save_function = 'custom_callback_function_name'; // Set to your callback function name.
 }
return $field;
}
add_filter( 'pmpro_add_user_field', 'my_pmpro_user_field_add_save_function_example', 10, 2 );
// Custom callback function
function custom_callback_function_name( $field_value ) {
 // Do something
}
view raw save-function-add-user-field-filter.php delivered with ❤ by Paid Memberships Pro

Save Function Example: Capitalize the Input Value Before Saving

In this practical example, we add a custom field to collect “Pet Name” for our Must Love Dogs demo site. Since name is a proper noun, we want to make sure our pet’s name is properly capitalized before saving it to the database. Here are the steps:

  1. Create a text input field that collects the pet’s name.
  2. Create a custom function that capitalizes each word in a string.
  3. Add the save_function option to our field calling our custom function to process the field handling.
<?php
// Create a registration form field with a custom callback
function my_pmpro_user_field_example_save_function() {
// Don't break if PMPro is out of date or not loaded.
if ( ! function_exists( 'pmpro_add_user_field' ) ) {
return false;
}
// define the fields
$fields = array();
// Basic Text Field Example
$fields[] = new PMPro_Field(
'pet_name', // input field name, used as meta key
'text', // field type
array(
'label' => 'Pet Name', // field label
'profile' => true, // display on user profile
'save_function' => 'my_capitalize_registration_field_value', // use a custom callback function
)
);
foreach ( $fields as $field ) {
pmpro_add_user_field(
'checkout_boxes', // location on checkout page
$field // PMPro_Field object
);
}
}
add_action( 'init', 'my_pmpro_user_field_example_save_function' );
// Custom callback function to capitalize string value
function my_capitalize_registration_field_value( $user_id, $field_name, $field_value ) {
// Do nothing if no value or if not string
if ( empty( $field_value ) || ! is_string( $field_value ) ) {
return;
}
// Captilize words
$field_value = ucwords( $field_value );
// Sanitize before saving to the database.
$field_value = sanitize_text_field( $field_value );
// Save to the usermeta table
update_user_meta( $user_id, $field_name, $field_value );
}
view raw my-pmpro-user-field-example-save-function.php hosted with ❤ by GitHub

Here’s an example of using this approach to create a custom save function to store more information for a Digital Signature-type field.

Adding the Recipe to Your Website

You can add this recipe to your site by creating a custom plugin or using the Code Snippets plugin available for free in the WordPress repository. Read this companion article for step-by-step directions on either method.

Writing the exact custom function to save your fields requires advanced WordPress and PHP development experience. This example is a fairly simple application of the power of a custom callback function but demonstrates the range of possibilities for how form inputs are handled.

I have personally found this custom callback to be the PMPro User Fields API superhero secret power, and I hope you find as much joy as I do from it. Remember to always sanitize your data before saving it to the database.

Theunis Coetzee

Author: Theunis Coetzee

Theunis Coetzee is a Support Engineer at Paid Memberships Pro. He began his career as a web and graphic designer before transitioning to web development and server administration. After a few years dedicated to photography and cooking, Theunis returned to the development field, ultimately joining Paid Memberships Pro’s support team.

He values the company’s mission, team spirit, and open-source commitment, appreciating the opportunity to contribute to the community and the greater good. He enjoys the variety of challenges and the collaborative "A" team that makes each day rewarding.

Outside of work, Theunis loves riding adventure motorcycles, wild camping, experimenting with exotic dishes, and spending time with his parrots at home.

View more articles by Theunis Coetzee »

Free Course: Membership Site Development—The Basics

Develop a deeper understanding of membership site development in this beginner-level course. Learn how to make your site work better, save yourself time and money, and improve your site's performance.

Take Free Course Now
Featured Image for Membership Site Development Course: The Basics


Was this article helpful?
YesNo